An MRI apparatus is for acquiring a magnetic resonance image (hereinafter referred to as an MR image) which represents the physical description of the object, when electromagnetic waves are irradiated to an object placed in a homogeneous static magnetic field, by detecting a nuclear magnetic resonance signal (hereinafter referred to as NMR signal) from the object using nuclear magnetic resonance (hereinafter referred to as NMR) phenomenon being generated in atomic nuclei of atomy by which the object is formed, and constructing an image using the NMR signals.
In MRI, a technique is known for imaging a wide range or a whole body of an object while translating a table on which the object is placed in a gantry of an MRI apparatus. In such technique, there are two ways for translating the table. One is the multi-station imaging method for dividing a wide range or a whole body of the object into a plurality of blocks, and imaging each block while translating the table step-wise (for example, refer to Patent Document 1). The other method is the moving-table imaging method for imaging a wide range or a whole body of the object while continuously moving the table (for example, refer to Patent Document 2).
Patent Document 1: U.S. Pat. No. 6,311,085
Patent Document 2: JP-A-2004-611
However, after reviewing the above-mentioned conventional techniques, the present inventors found the following problems.
In the above-mentioned conventional technique, in the case of imaging while translating the table continuously or step-wise and translation accuracy is low, since the image of the object is reconstructed by performing Fourier transformation etc. on the signal data obtained in the position on the object that is different from the original position meant to be imaged, the moving-table imaging method has a problem with motion artifacts being generated over the entire image, and the multi-station imaging method has a problem with a gap being generated between the adjacent stations (spatial regions which could not acquire a magnetic resonance signal) when excess amount of table translation is performed. While a technique is disclosed in Patent Document 3 for using navigator echoes to correct artifacts of the images obtained while the object is being translated, a technique related to the method on how to detect low-level of table movement accuracy (error in the case that the obtained positional data of the object is different from the original position meant to be obtained) in order to reduce deterioration of image quality is not disclosed.
Patent Document 3: JP-A-H8-173396